I've owned a pair of Optimus LX10 loudspeakers for about ten years now. About five years ago I noticed that the dipole ribbon tweeters on both speakers weren't producing any sound. The woofers were making noise just fine, just not the tweeters.
Fast forward to a couple weeks ago when I decided to try and fix them. I did some research on the interwebs and found a post on audioreview about a fuse on the circuit board inside the speaker that had a tendancy to blow.
I cracked one of the speakers open to check said fuse only to find that it is intact! Ok, lets check for leaky caps... nothing - it all looks good. What could be the problem here?
Do these tweeters go bad? I don't really understand how; I mean, they are a ribbon, magnets, and wiring - what component could fail?
Here is a picture of the circuit board. I have a digital multimeter, how can I test this circuit to check which component (if any) is defective?
Fast forward to a couple weeks ago when I decided to try and fix them. I did some research on the interwebs and found a post on audioreview about a fuse on the circuit board inside the speaker that had a tendancy to blow.
I cracked one of the speakers open to check said fuse only to find that it is intact! Ok, lets check for leaky caps... nothing - it all looks good. What could be the problem here?
Do these tweeters go bad? I don't really understand how; I mean, they are a ribbon, magnets, and wiring - what component could fail?
Here is a picture of the circuit board. I have a digital multimeter, how can I test this circuit to check which component (if any) is defective?
Attachments
measurement results
I placed the multimeter's probes on the spade connectors for the dipole tweeter. I set the digital multimeter selector to the 20M OHM range and got .2 on the readout.
I'm guessing this means that the tweeter is shot as I should get a reading of 6 with the selector set to 200 OHM right?
Thanks for your help so far.
I placed the multimeter's probes on the spade connectors for the dipole tweeter. I set the digital multimeter selector to the 20M OHM range and got .2 on the readout.
I'm guessing this means that the tweeter is shot as I should get a reading of 6 with the selector set to 200 OHM right?
Thanks for your help so far.
Hi masofshad,
yes, at range 200 ohms the tweeter should measure close to 6 ohms. If it reads 0.2 ohms, than its shorted. If it reads 0.2 Mohms, than its open/burned. In any case its not a good sign.
I took some of those apart, but was not able to put them back!
Yes, they are glued together. Time to get new tweeters.
How about this one:
http://www.partsexpress.com/pe/showdetl.cfm?&Partnumber=297-409
It's nice sit on top of the cabinet.
yes, at range 200 ohms the tweeter should measure close to 6 ohms. If it reads 0.2 ohms, than its shorted. If it reads 0.2 Mohms, than its open/burned. In any case its not a good sign.
I took some of those apart, but was not able to put them back!
Yes, they are glued together. Time to get new tweeters.
How about this one:
http://www.partsexpress.com/pe/showdetl.cfm?&Partnumber=297-409
It's nice sit on top of the cabinet.
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